Airplane



Oct. 27,

RI F. HALL AIRPLANE Filed Nov. 15, 1924 3 Sheets-Sheet 2 R. F; HALL- Oct. 27 1925- AIRPLANE Filod Nov. 15, 1924 3 Sheets-Sheet 5 Patented Oct. 27, 1925.

mnnorirn 1''. BALL, or r'r'ancn, new Yonx, assrenoa or DORE 2. BALL, or WALLINGFOBD, connnc'rrcu'r,

WILSON, OF ITHAGA NEW YORK,

ONE-FOURTH 'ro 'rrmo- Ann or oNE-roun'rn To run.

:AIBPLANE.

Application filed November 15, 11324. Serial No. 750,104.

T 0 all whom it may concern:

Be it known that I, RANDOLPH F. HALL, a citizen of the United States of America, ,and a resident of Ithaca, county of vTompkins, State of New ,York, have lnvented certain new and'useful Improvements in Airplanes, of which the following is a specification.

This invention relates to certain improvements in airplanes; and the nature and objects of the invention will be readily recognized and understood by those skilled in the arts involved in the light of the following explanation and detailed description of the accompanying drawings illustrating what I at present considerlto be the preferred embodiments of aerodynamical and mechanicalexpressions of the invention from among various other forms, arrangeiients, combinations, and constructions of which the invention is capable within the spirit and scope thereof.

The invention deals with the aerofoils utilized to form the lift or. supporting surfaces or wings for airplanes, and aims to increase the efiicienoy and range -'of operation of such aerofoils and of thesupporting surfaces or Wings formed thereby,- through the solution of certain problems and the reductionand substantial elimination of certain conditions encountered in use thereof which tend to decrease the efficiency of and theresults obtainable with these-supporting surfaces orwings in flight.

When an aerofoil is moved through the air at an angle of incidence,-ror when a stream of air is forcedv over an aerofoi'l dis pds'ed and maintained therein at anangle of incidence, a mass of the air is displaced downwardly with the resulting creation or establishment of an upward or lift force; The lift force so developed is dependent upon the positive" pressure created on the under side of theaerofoil and the negative pressure created abovethe' aerofoil, and is attended'by the establishment ,or creation of another force-acting in a rearward direction- 1 an'dgenerall referred to asthe drag force,

which must e overcome in operation of the aerofoil as a lift or supporting surface. The ratiobetween or the proportion of the rearward acting or drag force to the up- .ward acting or lift force of an aerofoil determines the relative efiiciency of the aeroo ing foil and it follows, therefor, that the greater the lift force for a given or minimum drag force, the higher the efiiciency of such aero-' foil. The lift force of an aerofoil increases with the increase .of the angleof incidence h I up to a certain angle known as the criti-' cal angle of the aerofoil, at which point the lift force falls off or decreases with an increase in the angle of incidence, so that each aerofoil has a limited range of opera tion from low incidence to maximum high incidence or the critical an le ofthe aerofoil,the operating range, 0 course, vary- I with the particular aerofoil and the characteristics thereof.

In an airplane the supporting surface :or

wving forming aerofoils thereof create the desired upward or lift force by the application of power to move these supporting surfaces or wings through the air at an angle of incidence and tothus displace av mass of the air, and the rearward or drag forces overcome by the power, so that the airplane is sustained and capable of flight. The flight conditions of the airplane'vary. from the 'high speed and low wing incidence condition, to the low speed and high wing incidencecondition. In the low wing .incidence condition the maximum or high speed i of the airplane is obtainable by the application of the full power which canbe delivered, and the determining factor in this high speed and low wing incidence condition is the relation of the lift force to the drag force of the win as willbe readily ap- "parent to those skilled in)v this art. At high f wing incidence with resulting low speed of .'the airplane, surplus power is generally present and maximum lift forceis the prime face or. wing forming aerofoil in an airconsideration and the mainrequirement. It follows, therefore, that a supporting sur plane, whichembodiesand incorporates the characteristics of both a very high lift force at high wing incidence and low speed con- 'ditions, and ahigh Iift/drag value at low wing. incidence. conditions, is of high efii yciency and permits of operation of the fairplane to secure substantially maximum efliciency. in performance. F I I The present invention is directed to and presents as one of its fundamental objects,

the provision of supporting surface or wing forming aerofoils for airplanes which will embody and incorporate the foregoing characteristics of high lift at high wing incidence and a high lift/drag value at low wing incidence to secure a maximum efliciency in operation, as well as to increase the operating range of a wing by permitting efiicient operation thereof at higher angles of incidence with resulting increase in the lift force developed, through an increase in the critical angle of the win A main characteristic of the invention resides in forming an airplane supporting surface or wing which will be capable of displacing a larger mass of air with the wing under high incidence conditions and thus correspondingly create or develop a greater upward or lift force, without materially decreasing the efficiency of the wing as determined by the lift/drag ratio, under low incidence and high speed conditions, and further, in which the critical angle of the wing increased to permit of operation at higher incidence angles and over a greater range thereof without material decrease or variation in the maximum lift force developed by the wing at such high incidence angles.

Another characteristic of the invention consists in forn'iing an airplane supporting surface or wing, of superposed aerofoils or lift surfaces disposed spaced apart at a relatively small gap/chord ratio to form an air passage therebetween through which air is displaced downwardly with the wing at high angles of incidence, with resulting increase in the air mass displaced by the wing and incerase in the upward or lift force thereof.

A further characteristic of the invention embodies the provision of a wing or supporting surface formed of the spaced, superposed aerofoils providing the air displacementpassage therebetween, in which the wing so formed is convertible by closmg the air displacement passage at low angles of incidence to provide athlck section wing having efficient high speed, low incidence characteristics.

Another. characteristlc of the inventlon presents an airplane supporting surface or wing formed of superposed and spaced aero foils providing an ear displacement passage therebetween having vanes or flaps operable to close the passage at the leading and trailembodying the spaced, superposed aerofoils, which are sloped or inclined downwardly and rearwardly to-discharge into the displacement passage between the areofoils with the object in view of causing a further displacement of air through these slots to accelerate and increase the air displacement by the win Another characteristic and feature of the invention consists in the manner of mounting the superposed aerofoils in the desired spaced relation to secure a rigid structure having the desired structural strength and aerodynamical efiiciency, which mounting will be of the desired simplicity in structure 30 and arrangement.

\Vith the foregoing general objects and characteristics, and certain other objects and results, in view, which other objects and results will be readily apparent from the following description, the invention consists in certain novel features in construction and in aerodynamical and mechanical arrange- 'ments and combinations of elements, will be more fully and particularly referred to and specified hereinafter. Referring to, the accompanying drawingsz Fig. 1, 1s a view in end elevation, more or less diagramniatical, showing a. wing of the invention formed of the superposed aerofoils with the flaps for closing'the passage therebetween' to convert the wing to a single relatively thick section type, the flaps being disclosed in open position with the closed position thereof indicatedin dotted outline.

Fig. 2 is a view similar 'to Fig. 1 and more or less diagrann'mitical, showing a different arrangement of superposed acrofoils 1 vanes or flaps for closing the air displaeelnent passage, a formation of slots through the upper acrofoil being indicated by dotted lines;

Fig. 4, is a more or less din-grammatical view in end elevation of a wing formed of three superposed aerofoils with an arrangement of vanes or flaps for closing the air 2 displacement passages therebetween to convert the wing to a thick section type.

i Fig. 5,is adiagrammatical view, partly in elevation and partly in section, of a wing embodying the invention, showing the mauner of structurally mounting-and securing the superposed aerofoils in spaced relation toform a unit structure. I Fig. (i, is .a diagrammatical view in elevation of a form of wing of the invention e1n- 9 less diagra'm- I 110 bodying the superposed aerofoils and an arrangement of vanes or flaps for closing the displacement passage, in which a series of longitudinally downwardly and rearwar .inter-aerofoil trussing system of Fig. 5.

Fig. 9, is a more or less diagrammatical perspective view of a portion of a wing embody the invention and showihg a possible mechanical arrangement of operating mechother forms and embodiments involving the anism for the vanes or flaps.

.Fig. 10, is'a fragmentary detail view in elevation showing an arrangement of aileron and of a displacement closing vane or flap on a wing of the invention.

Fig. 11, is a more or less diagrammatical view in planof a wing formed with a portion thereof embodying the invention, while the outer or tip portion thereof is of conventional design.

In the accompanying drawings several possible aero-dyna'mical and mechanical expressions ofthevarious features and principles of the invention, are more or less. diagrammatically disclosed purely by way of examples and not of limitation for the purpose. of exemplifying and explaining the invention to enable those skilled in the 'art to understand the same. It will, however, be readily apparent from and'after the following description. and explanation, that the principles and features of the invention can be aerodynamically and mechanically ex' pressed in various other forms and presented by other embodiments than the examples illustrated and explained herewith, and the invention so contemplates and includes such principles and viuious features of this in ventlon.

A supporting surface or wing for an air-.

plane which embodies the principles and certain features of the invention is illustrated by Fig. '1 of the accompanying drawings. In this form of the invention a pair of lift surfaces A and B are superposed in spaced relation with the leading and trailing edges of the lower aerofoil B in advance of the leading and trailing edges, respectively, of the upper aerofoil A, that is with these superposed aerofoils negatively stage-=1 gered. The aerofoils are suitably fixed together in spaced relation and form and provide an ,air displacement passage 10 therebetween 'normall open across and at the leading and trai ing edges of the aerofoils A and B. The'depth of this passage 10 is such as to provide an eflicient gap /cord ratio between the aerofoi-ls A and B, as determined by the characteristics of the aerofoils, so as to secure the desired air displacement dly inclined slots are formed through the upper.

"displaced with a at. high incidence to swing vertically on the horizontal axis 1 I 21 to position shown in dotted outline extending upwardly'across the passage 10 and rearwardly to the leading edge. of the upper aerofoil to clo'setheforw'ard end of passage- 10 and form a continuation of the upper aerofoil A merging into the leadingedge of the lower aerofoil B. The vane 20 in normal. position; swung downwardly to open passage 10, is shown infull lines, in which position vane 20 rests upon the uppersurface of the lower aerofoil B and forms an outward, forward continuation thereof. A flap or vane 30 is pivotally mounted on a horizontal axis between the trailing edge portions of the upper and lower aerofoils and B, and this vane 30 is mounted with-,

the axis 311,.extending therethrough intermediate the forward and rear edges thereof, so that the vane is rotatable or capable of oscillation thereon to swing the rear edge portion upwardly and theforward edgeportion downwardly to the position shown in dotted outline with the vaneextending across and closing passage 10 between the trailing edges of aerofoils A and B in upward and rearward continuation of the, lower aerofoll B. Inopen position, shown in full lines in Fig. 1, the rear vane or flap 30 is swung to position intermediate .and a spaced from the upper and lower aerofoils A and B, respectively, to'open the trailing end of passage 10. v

The design and arrangement ofthe upper and lower aerofoils A and B, andthe forwith the forward and rear vanes swung to position closing passage 10', the wing unit is converted to a sin le relatively thick section type of wing iaving sucha section and characteristicsas to deve op an efficient lift/drag value at lowv incide ce and high speed conditions. high incidence and low speed conditions where maximum lift is desired, the forward andirear vanes are swung to open position which opens the passage 10 and -results in a displacement of air downwardly and rearwardly "therethrough. This displacement of air through passage 10 is in addition to and augments the-normal displacement by aerofoils Aaud B, and increases the total niass resulting increase in the upward or lift force developed by the wing Further, the range of hi h incidence'angles of the .wing is exward and-rear vanes 20 and 30, is such that tended, that is, the eritical angle for the In'flight/operation under &

wing is increased so that it maybe operated at higher angles of incidence and the lift force created remains substantially constant without material decrease over the range of high incidence angles made possible. In the foregoing manner the etliciency and performance of an airplane equipped with wing units embodying the foregoingprinciples is materially increased, as the speed range is increased as well as the weight which may be carried, so that a more etlicient loading is possible and a slower landing speed secured without material decrease in the efficiency at low incidence and high speed. Likewise the possible flying speed is decreased to permit of slow'speed without danger of stalling or loss of flying speed and control of the airplane.

A wing'embodying the invention is disclosed in Fig. 2 as presenting another form and arrangement of aerofoils and vanes or flaps. In this form of the invention aerofoils A and B of suitable section are superposed in spaced relation to form the air displacement. passage 10. and the upper aerofoil A is provided with a trailing edge flat 30 in rearward continuation thereof and pivotally mounted thereon along the horizontal axis 31. The lower aerofoil B is provided with a similar trailing edge flap 32 in rearward continuation thereof pivotally mounted thereon along the horizontal axis The leading edge portion or for- 'ward section of the lower aerofoil l3 is their trailing edges engaged to close. the rear end of passage 10, and the forward flap 20 of lower aerofoil it is in position engaging the leading edgeof aerofoil A to close the forward end of passage it), as shown in full lines in Fig. 2. The. passage 10 is opened with the wing unit at high incidence to permit displacement of air therethrough, as

hereinbefore explained, by swinging for ward flap '20 don"nward-ly, and swinging the rear fla )S 30 and 32 to disen a ed diver ed and open position. The displacement passage opening position of the flaps 20', 30 and 32 are indicated by dotted lines in Fig. 2. Itwill here be noted that the rear flaps 30 and--32 are of the aileron type and the invention contemplates and includes the use of either or both of these flaps as lateral control surfaces or ailerons for such a wing inan airplane, the operation of which can conform :to/ conventional practice well understood in this art.

In' the form and embodiment of the 'in- Vention presented in Fig. 3, the superposed,

spaced aerofoils A" and B are arranged with the leading edge portion of the upper aerofoil A extended forwardly beyond the lower aerofoil B, and a vain 20 ispivotally mounted on a horizontal axis 21" along the under surface of upper aerofoil A adjacent. the leading edge thereof. This vane 2t is swingable downwardly, as shown in dotted lines, to position across and closing passage 10 and forming a substantial upward and forward continuation of B to the leading edge of upper aerofoil A". In position opening passage 10, the vane 20 is swung upwardly against the under side of aero'foil A, as shown infull lines. A trailing edge flap 32, similar to that of Fig. 2, is pivotally mounted on lower aerofoil l for swinging movement upwardly'to position across and closing the rear end of passage 10 and forming an upward continuation of aerofoil B", to the trailing edge of aerofoil A, as shown by dotted lines. The i open, high incidence position of vane 20 and flap 32 to open air -displacement passage 10, is shown in full lines.

The invention presents another feature in the provision of slots through the upper aerofoils to aid in the. air displacen'ient through passage 10, and one possible arrangement of such slots is indicated by dotted lines in Fig. 3, and further referred to in connection with the disclosures of Figs.

(3 and 7, hereinafter. In Fig. 3 the upper aerofoil A is formed with the longitudinal slot 40 extending upwardl and rearwardly through the forward portion thereof to the rear of vane 20", and the longitudinal slot 41 spaced rearwardly from slot 40 and extending upwardly and forwardly through the aerofoil. These slots 40 and 4-1 both comminiicate with the displacement passage It), and at their outer ends open to and coalmunicate with the atmosphere.

In Fig. 4 of the accompanying drawings the invention is presented in a wing formed of the series of spaced superposed aerofoils or lit't surfaces A, it, and (.1, arranged in negatively staggered relation and providing the air displacement passages 10 and 10 therel'ietween, respectively. A vane 22 is pivotally mounted on the horizontal axis 23 intermediate the leading edges of the upper and intermediate aerofoils A and B, respectively, and asimilarvane 22 is pivotallv mounted on a horizontal axis 23' intermediate the leading edges of the intermediate and lower aerofoils B and C, respectively. The vanes 22 are swingable to the full line positions extending across and closing the leading or forward ends of the displacement passages 10 and 10, respective] and likewise connecting and extending iietween the leading edges of aerofoils A, B and C, to form a surface in continuation of the up er surface of aerofoil A extending downwar 1y and forwardly to the leading edge of aerofoil B. These-vanes 22 are further swing able to the dotted line. positions disposed intermediate the aerofoils A, Band C, respectively, to open the forward'ends of'the air displacementpassages 10 and 10' betweentheaerofoils. Vanes 30 are pivotally mounted on horizontal axis 31 intermediate the trailing edges of the upper and in- H termediate aerofoils A and B, and the trail ing edges of the intermediate and lower I aerfoils B and C, respectively, and these vanes 30 are swinga'ble to close the rear or trailing ends of passages and 10, respectively,.with the vanes extending between the trailing edges of aerofoils'A, B and C, and forming an upward and rearward con-. tinuation of the lower surface of aerofoil C, to the trailing edge of ae-rofoil- A, as-

shown in full lines by Fig. 4. The position of vanes to open passages 10 and 10", respectively, between aerofoils A, B and C, is indicated in dotted outline. Thus, the wing I of Fig. 4, is operable at high incidence condition with vanes 22 and'3O swung to position openlng passages 10 and 10 to permit displacement of air therethrough to increase the lift force of the-wing unit, as hereinbefore explained, while at-low incidence the vanes 22 and 30 are swung to close passages 10 and 10', and convert'the wing unit. into a single thick section type wing.

Another possible form and arrangement of vanes for closing the forward or leading opa'ho'rizontal axis 25 disposed forward or inadvan ce of the leading edges of the upperend'of the air'displaceinent passage 10 between superposed aerofoils A and B .embodying a wlng of the invention is disclosed in Fig. 5. In this form of-the invention the aerofoils A and B are superposed to provide the displacement passage 10. therebetween and therear or trailing end of the passage is adapted to be opened and closed by the pivotally mounted vane 30 swingable on the horizontal axis 31 intermediateathe trailing edges of the aerofoils, in a manner hereinbeforew described and explained. Complementary upper and lower vanes 24 and 24' are mounted lower 'aerofoils 'A and-Bfland swingaijleaaway" from each other or upwardly and downwardly'respec'tively, to the dotted line position extending across and closing the forward or leading end of passage 10,

with the upper vane 24: forming a forward and downward continuation of aerofoil A? and the lower vane 24' forming a forward and upward continuation of aerofoil- B. Thus, in 'assage closing position (dotted lines) of t e forward vanes 24= a'nd 24' and the rear vane 30, the passage 10 betweenaerofoils A and B is closed, and a single thick section t 0 win is formed for low incidence condit ons, w ile m passage opei1-' ing'position (full lines) of these vanes the high lift, hi h incidence wing involving the principles-o the invention is presented.

-A further feature of theinventi n a plicable to the various forms of wings disc osed and described herein, is illustrated in Fig.

5, in connection with Fig. 8, and embodies a structural arrangement for. mounting and securing the superposed aerofoils in there-t I quired spaced, air displacement passage providing relation to form the wing of the mvention. Theupper and lower aerofoils A and B, referring to Fig. 5, are formed with usual front and rear wing spars or girders F and B, respectively, or any equivalent structure, which are in substantial vertical alinement with the aerofoils in proper superposed relation. Accordingto this fea 'ture of the invention suitable bracing or the requirements of each particular installation, without going beyond the broad principle of the invention, and further that such arrangements are applicable to the various 1 forms of the wingof the invention disclosed,

as well as other forms embodying the invention- In Figs. 6 and 7 ofthe drawings a wing of the invention is disclosed consisting of upper aerofoil A and lower-aerofoil B disposed in spaced superposed relation and having a forward passage closing vane 20 and a rear, assage closing vane 34. In this instance orward vane'20 is pivotally mounted on axis 21 alon the leading edgeof lower aerofoil B an rear vane 34 is pivotally mounted on axis 35 along'the trailing edge of lower aerofoil B. The operation of these vanes will be clear from the foregoing descriptions and are swingable-to open-passage 10 for high incidence conditions,'or-to close passage 10 and'convert the wing unit into a single thiek' section type for low incidence conditions. The u per aerofoil'Ai is formed with the substantlally' parallel, spaced slots thereof intermediatethe leading and trail-- fing edges of theaerofoil. These slots 5 0 open through the npp'er'snrface'of aerofoil A? and extend downwardly therethrough at a-rearw'ard inclination, to and discharging form of win wing at high incidence andpassage 10 open,

v "50 extending thereacross and longitudinally 1 "into the air displacement passage 10 between the aerofoils- A and B. In operationofthej of Figs. 6 and 7, with the."

air is displaced through this passage, as explained, and is likewise drawn through slots in the upper aerofoil to assist in increas-' ing the air displaced by the wing under high incidence and high lift conditions. The in yention is, of course, not limited to the number of slots or their exact shape and form as disclosed in the example .of this feature of the invention presented by Figs. 6 and 7.

A possible form of operating mechanism for the forward and rear vanes for opening and closing the air displacement passage of a wing of the invention, is more or less diagrammatically illustrated in Fig. 9 of the accompanying drawings. A wing formed of the superposed aerofoils A and B having'the displacement passage 10 therebetween, and the forward vane 22 and rear vane 32 pivotally mounted on the axis forming shafts 23 and 33, respectively, is shown,

in which the shaft 23 for the forward vane 22 is pivotally mouniel intermediate the leading edges of the rofoils on bearings 26 suspended and supported from the aerofoils by suitable hangers or the like 27, while the rear vane or flap 32 is pivotally mounted by shaft 33 along the trailing edge of the lower aerofoil B The shafts 23 and 33 are extended at one end of the wing and shaft 23 is provided with a bell crank fixed thereon, while shaft 33 has an arm 64 mounted and fixed thereon. A rod or tube 63 connects arm or crank ti l-on shaft 33 with one arm of the.bell crank 60 on shaft 23. At any desired position, preferably accessible to the pilot of an airplane of which the wing forms a part, a hand operating lever 62 is mounted on a shaft 65 and is provided with an arm 66 operatively connected with the bellcrank 60 on shaft 23, by the rod or link 61. Thus, by operating lever 62, the shafts 23 and 33 are simultaneously rocked or rotated to swing the vanes 22 and 32 to passage opening position, or to passage closing position. as will be clear by reference to Fig. 9 of the drawings. If desired or found expedient, the front and rear vanes can be separately and independently operated by suitable mechanism and it is not intended by the illustrated example to limit the invention to simultaneous operation of these vanes' The mechanism illustrated is merely for the purpose of an example to show a possible manner of operating the vanes, and it will be obvious that various other arrangements and mechanical expres sions for operating the vanes may be employed to fulfill the conditions presented by the type, form and arrangement of the vanes or flaps utilized.

The .fear vanes or flaps of the wings of the invention can be utilized to provide and form the lateral control surfaces or ailerons for the wing on which mounted, and can be operated and controLled by the usual 01;

any other desired mechanism for this pursu er )osed aerofoils A and B havim the rear flap 32 for opening and closing the rear or trailing end of displacement passage 10, and an aileron or lateral control surface 36 is pivotally mounted along the trailing edge of aerofoil A in substantial continuation thereof, and operable in the usual or any desired manner familiar in this art.

A form of wing W, is disclosed in Fig. 11 of the drawings, embodying the spaced,

superposed aerofoils A and B to form pas sage 10 therebetween, and having the passage closing vanes 22 and 32, all arranged and mounted in accordancev with the principles of the invention, in which the outer end or top portion 0 of the wing is formed of conventional design having a section substantially conforming to the section of wing W when converted by vanes 22 and 32 to the single thick section wing for low incidence-high speed conditions, or to one of the superimposed sections. The conventional tip portion 0 of the wing is provided with the usual or other aileron or lateral control surface 37. Thus, an airplane wing or supporting surface can be formed having a art or section thereof formed to embody the principles of the invention hereof, and the remaining part or section thereof formed in accordance with the conventional or other types of wings.

By the invention, a-n'airplane supporting surface or wing is provided in which highefliciency is obtained through an increase in the lift developed at high angles of incidence and an increase in the range of high incidence angles is secured without material decrease or variation in the lift over the range of high incidence, while retaining in the wing the desired characteristic'of high lift/drag value at low incidence. through the convertible features of the invention. In this manner. an airplane equipped with wings of the invention can be more etiicient- 1y loaded and its range of operation materially increased, including an increase in the speed range of the airplanewitha minimum low flying speed. I

In those forms of the invention including slots or openings in the aerofoils. any suitable means may be employed, such as shutters, vanes orthe like. for opening and closing such slots or openings if found expedient or desirable. and such means may take the form of the vanes or flaps dis- I closed for opening or closing the wing air displacement passages. Further, attention is directed'to the fact that any suitable number or arrangement of aerofoils'or lift surfaces maybe employed to form a wing embodying and presenting the broad principles of the inventi'on, and it is not. intended to restrict the invention to the number of aelarofoils disclosed in the illustrated examp es.

wing is employed in a broad, generic sense stitutlons'might be resorted to without departing from the spirit and scope of my invention, and hence I do not desire tolimit myself to the exact' and specific disclosures hereof.

Desiring-to protect my invention in the broadest mannerlegally possible, what I claim is: w

lgAn airplane wing embodying superposed' aerofoils spaced apart to form an air and displacement passage therebetween, means for opening' and closing said passage. 2. An airplane wing embodying super:

posed aerofoils spaced apart to form an airdisplacement passage means for opening and closing the forward and rear ends of said passage.

- therebetween, and

3. An airplane wing havingan air dis placement passage extending therethrough from leading totrailino ed e thereof, and meansfor closing said passage to convert said wing into a substantially unbroken sursaid aerofoilsfandclOsing the forward faced wing. I

4. An airplane wing embodying superposed aerofoils spaced apart to provide an air displacement passage therebetween, and means for closing said passage to convert the aerofoils to form a single wing section.

5. An airplane wing embodying superposed aerofoils spacediapart to provide" an air displacement passage therebetween, and means for connecting the leading edges of said passage.

6. An airplane wing embodying superposed aerofoils spaced to provide an air displacement passage therebetween, means for connecting the leadingedgesof said aerofoils and elosingthe forward end of saidpassage, and'means forconnectingthe trailing edges of'said aerofoils and closing the rear end of said passage. 7 w

7. An airplane wing embodying superposed aerofoils spaced to provide an air displacement passage therebetween, means apex-able to extend between and; join the In the appended claims the. term airplane leading edges of said'aerofoils to close the forward end of said passage, means operable to extend between and connect the trailing edges of saidaerofoils to close the rear end of said passa e, the said means-1n passage closing positions converting said aerofoils'to a single wing.

8. An airplane embodying superposed aerofoils spaced to provide an air passage said passage.

9.An airplane wing embodying superposed spacedaerofoils providing an air displacement'passage therebetween, and pivoted members operable to close said passage.

10. An airplane wing embodying super- "posed aerofoils spaced to provide an air dis placement passage therebetween, a member .pivotally mounted at the forward end of said passage, is member pivotally mounted therebetween, and vanes operable to close at the rear end of said passage, and .thesaid 1 members operable to open and close said -passage.

11. In. an airplane wing, superposed aerofoils spaced'to provide anair displacement passage therebetween, and members operable to close the forward and rear ends of said passage andconvert said spaced aero foiis 1nto a single wing section.

' 12. In an airplane wing, superposed aerofoils spaced-to provide an air displacement passage therebetween, members operable to close theforward and rear ends of said passage, said members in passage closing position converting said spaced aerofoils into a single wing section, and means for operating said members. p I

13. Inan airplane wing, superposed aerofoils spaced to provide an air displacement passage therebetween, members operable to close the forward and rear ends of said passage and convertsaid spaced aerofoils into a single Wing section, and means for simult-aneously operating saldmembers. 14. An alrplane wing embodylng spaced aerofoil sections in fixed relation, and means forconverting said spaced sections into a single aerofoilsection.

15. An airplane Wing embodying spaced upper .and lower aerofoil' sections in fixed relation, and means for converting said spaced sections into a single aerofoill section. 16. An airplane wing embodying super: posed aerofoils spaced to provide an airdisplacement passage I 'therebetween, ,members -for closing said passage,fand certain of said members operable as lateral controlelements for said wing; p k I 17. An. airplane wing embodying superposed aerofoils spaced to provide anair displacement passage therebetween, members at the forward and rear ends of said passage for opening and closing the same, and said rear members operable as the lateral control elements for said wing.

18. An airplane wing embodying super-e posed aerofoils spaced to provide an air displacement passage therebetween, a member at, the forward end of said passage and a. member atthe rear end of said passage, said members operable to open and to close the said passage, and said rear member i'orn'iing a lateral control element for the wing.

19. An airplane wing embodying superposed spaced aerofoils, and the upper aerofoil formed with a series of longitudinally disposed, substantially parallel slots extending therethrough and inclined downwardly and rearwardly.

20. An airplane wing embodying superposed spaced aerofoils providing an air displacement passage therebetween, the upper aerofoil formed with slots extending therethrough in communication with said dis placement passage, and means for opening and for closing said air displacement pas-' sage. r

21. An airplane wlng embodying superosed s )aced aerofoils rovidin an air displacement passage therebetween, the upper aerofoil formed with air passages extending therethrough in communication with said displacement passage, and means for closing said air displacement passage at the forward and rear ends thereof to convert saidaerofoils to a single wing section.

22. v An airplane supporting surface or wing embodying superposed and spaced aerofoils having a. relatively small gap/chord ratio, trusses rigidly connecting and securing said aerofoils in superposed relation, and means for converting said aerofoils to form a single wing section.

23. An airplane supporting surface or wing embodying superposed and spaced aerofoils having a relatively small gap/chord ratio, each of said aerofoils including a front and rear wing spar, trusses rigidly connecting the front spars and the rear spars, respectively, of said aerofoils tosecure the samein fixed superposed wing forming relation, and means for converting said aerofoils to form a single wing section.

means for converting, said fixedly spaced aerofoils to form a single wing section.

26. An airplane wing formed with an air displacei'nent passage extending therelhrough from leading to trailing edge thereof: to cause displacement of air downwardly with the wing at high incidence angles, and means for closing said passage with the wing at low incidence angles.

27. An airplane wing formed of superposed aerofoils spaced to provide an air displacement passage therebetween to displace air downwardly therethrough with the wing at high angles of incidence, and means for closing said passage to present the wing as a single relatively thick section at low angles of incidence.

28. An airplane wing formed of superposed aerofoils spaced apart and having a relatively small gap/chord ratio, the said aerofoils providing an air displacement pas: sage therebetween to cause displacement of air downwardly therethrough with the wing at high angles of incidence, and means for closing the leading and trailing ends of said passage to present the wing as a single relatively thick section at low angles of incidence.

29. An airplane Wing embodying aerofoils spaced apart to form an air displacement passage therebetween, lateral control elements for said Wing, and means for closing said passage to convert said aerofoils to form a single wing section.

30. An airplane wing embodying aerofoils spaced apart to form an air displacement passage therebetwecn, lateral control elements for said wing, and members operable to open and close said air displacement passage.

31. An airplane wing embodying aerofoils spaced apart to form an air displacement passage therebetween, an aileron on one of said aerofoils, and members operable independently of said aileron to close said passage and convert the aerofoils to form a single wing section.

'32. An airplane wing embodying a series of aerofoils spaced apart to form air displacement passages therebetween, and members for closing the air displacement passages to convert said aerofoils to from a sin le Wing section. p

Q igned at Ithaca, New York, this 6th day of November, 1924.

RANDOLPH F. HALL. 

